1. Technical Field
This invention relates generally to a hinge for folding seats or arm rests of the type used in passenger vehicles and, more particularly, to a hinge mechanism having an inertia-sensitive latch assembly that permits the seat or arm rest to be deployed during normal use but prevents deployment when the vehicle is subjected to deceleration forces exceeding a predetermined threshold level.
2. Discussion
The recent increase in popularity of pick-up trucks, mini-vans, and sport utility vehicles have led to certain advancements in the use of space for these vehicles. Particularly, there has been an interest in developing seat assemblies that provide increased cargo areas and improved accessibility to storage space. Consistent with this focus, seats that are movable between a stowed position and a deployed position have been developed for use with pick-up trucks, minivans, and sport utility vehicles. Passenger vehicles also commonly include armrests or center consoles located between adjacent seats that are similarly movable between stowed and deployed modes during normal operation.
Typically, the seat or armrest includes hinge supports on one or both opposed sides thereof for pivotal movement between the stowed and deployed positions. The hinges include upper and lower hinge members where the upper hinge member commonly rotates with respect to the lower hinge member about a pivot. The lower hinge member is commonly connected to the frame structure of the seat or vehicle floor depending upon the particular application.
While the above identified hinge assemblies effectively use space and enhance comfort, these assemblies can unexpectedly move from the stowed position toward the deployed position during a sudden vehicular deceleration caused, for example, by a frontal collision or heavy braking of the motor vehicle. Additionally, unexpected movement from the stowed position toward the deployed position can occur more frequently as the hinges wear and become loose. Therefore, a hinge for use in folding passenger seats and armrests that addresses the above deficiencies by inhibiting unexpected movement is desirable.
Although inertia-sensitive hinge mechanisms incorporating some of the above-noted features are commercially available and perform satisfactorily for this intended purpose, a need exists to provide continuous improvement in this field of technology for reducing system complexity and costs while also enhancing operational reliability and durability.
Accordingly, the present invention is directed to providing an improved hinge mechanism of the type having an inertia-sensitive lockout assembly. The inertia-sensitive hinge mechanism allows rotation of a first hinge member relative to a second hinge member about a pivot during normal use and prevents rotation about the pivot when a predetermined deceleration force is present. The inertia-sensitive lockout assembly includes a guide assembly coupled to the first and second hinge members. The guide assembly includes a tab fixed for movement with one of the first and second hinge members and a follower coupled to the other of the first and second hinge members for movement between a detent position and a cam position. The follower engages the tab for movement between a first position wherein the follower operatively engages a first tab detent and a second position wherein the follower operatively engages a second tab detent. The follower is in its detent position when the follower is in the first or second positions and its cam position when engaging a cam surface of the tab that extends between the first and second tab detents. The inertia-sensitive lockout assembly also includes an inertial actuator operatively connected to and rotatable with respect to the other of the first and second hinge members between a blocking position and a retracted position. The inertial actuator has a center of gravity spaced from its center of rotation wherein, when the follower is in its first position and the predetermined deceleration force is present, the deceleration force places the inertial actuator in its blocking position such that a blocking surface on the actuator blocks the follower from moving from its first position.
In another feature of the present invention, the center of gravity of the inertial actuator is located above and horizontally rearward of its center of rotation.
In yet another feature of the invention, the guide assembly guides rotation of the first hinge member with respect to the second hinge member and includes a pin upon which the follower is disposed for axial movement therealong between its cam and detent positions.
In still another feature of the invention, the inertia-sensitive lockout assembly includes actuator stop means and a spring that urges the inertial actuator against the stops when the actuator is in its blocking and retracted positions to prevent vibration of the inertial actuator.
In a further feature of the present invention, the inertia lockout assembly is part of an inertia-sensitive hinge mechanism intercoupling a first hinge adapted to be connected to a seatback and seat bottom and a second hinge member adapted to be coupled to a vehicle.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art after studying the following specification and appended claims taken in conjunction with the accompanying drawings.